Wear resistant poly (aryl ether ketone) polyimide blends

Abstract

Blends comprising (A.) at least one poly(aryl) ether ketone), and (B.) at least one polyimide having repeating units of the formula <IMAGE> (I) wherein R1 is a substituted or unsubstituted tetravalent radical having benzenoid unsaturation, and R2 is a substituted or unsubstituted divalent group having aromatic unsaturation which is essentially free of (i) backbone ether oxygen bonded directly to the aromatic ring forming an imide linkage and (ii) amide linkages bonded through carboxyl groups bonded to the aromatic ring forming an imide linkage. The blends exhibit good melt processability and wear resistance greater than the individual blend components.

What is claimed is: 
     
       1. A blend comprising A. at least one poly(aryl ether ketone), and   B. at least one thermoplastic polyimide having repeating units of the formula ##STR18## wherein R 1  is a tetravalent radical having benzenoid unsaturation, and   R 2  is a divalent group having aromatic unsaturation, which polyimide is essentially free of (i) backbone ether oxygen bonded directly to the aromatic ring forming an imide linkage and (ii) amide linkages bonded through carboxyl groups bonded to the aromatic ring forming an imide linkage.   
     
     
       2. The blend of claim 1 wherein said polyimide is present in the amount of about 2 to about 50 weight percent based on the weight of A and B. 
     
     
       3. The blend of claim 1, wherein said polyimide is present in an amount between about 10 and 35 weight percent based upon the weight of A and B. 
     
     
       4. The blend of claim 1, additionally comprising a filler. 
     
     
       5. The blend of claim 4, wherein said filler is selected from the group consisting of particulate polytetrafluoroethylene, molybdenum disulfide, graphite and carbon fibers. 
     
     
       6. The blend of claim 4, wherein said filler is present in an amount between about 5 and about 50 weight % based on the weight of the filled blend. 
     
     
       7. The blend of claim 1 wherein the poly(aryl ether ketone) contains repeating units of one or more of the following formulae: ##STR19## wherein Ar is independently a divalent aromatic radical selected from phenylene, biphenylene or naphthylene, X is independently --O--, ##STR20## or a direct bond and n is an integer of from 0 to 3, b, c, d and e are 0 to 1 and a is an integer of 1 to 4. 
     
     
       8. A blend as defined in claim 7 wherein the poly(aryl ether ketones) have repeating units of one or more of the following formula: ##STR21## 
     
     
       9. A shaped article formed from the blend of claims 1 or 7. 
     
     
       10. A shaped article as defined in claim 9 in the form of a bearing. 
     
     
       11. A shaped article as defined in claim 9 in the form of a seal. 
     
     
       12. A shaped article as defined in claim 9 in the form of a backup ring.